This invention generally relates to Stirling cycle engines. The Stirling cycle, invented over 150 years ago, utilizes external combustion and takes advantage of the principle of regeneration to recapture heat which would otherwise be lost from the cycle. In the form of the Stirling cycle disclosed herein, heat from the external source of combustion is utilized to heat a chamber at one end of an open-ended cylinder. Within the cylinder, a displacer piston and a power piston co-axially reciprocate, with the displacer piston being at the closed or heated end of the cylinder and the power piston being at the open end of the cylinder.
One feature of the present invention involves the mechanism by which the reciprocation of the power piston is converted to rotation of an output shaft oriented parallel to the axis of piston reciprocation.
Another feature of the present invention relates to a novel means by which the reciprocation cycles of the two pistons are inter-related according to a predetermined phase angle.
The present invention is intended to be used in applications where long maintenance-free operation is essential, with dry lubrication. It is therefore essential to minimize the side loading between the power piston and the cylinder walls. Another feature of the present invention therefore involves the isolation of the power piston from lateral forces induced as reactions to the output torque or drive line forces.
Part of the thermal efficiency of a Stirling cycle engine involves the cooling down and contraction of the gas between the two pistons after the power stroke, to aid in the return stroke of the power piston. The present invention also involves an improved displacer piston construction to thermally insulate the cooling space end of the displacer piston from the heated end of the displacer piston.
These and other objects of the present invention will become more readily apparent from the detailed disclosure which follows.